Extraction of metals from their ores.



W. HOMMEL '& H. T. DURANT. BXTRAGTION'OF METALS FROM THEIR GRES. APPLICATION FILED JUNE 25. 1910.

1,009,750. Patented Nov. 2s, wu'.

UNITED STATES PATENTL OFFICE.

WOLDEIVIAR HOMMEL AND HENRY THOMAS DURANT, OF LONDON, ENGLAND, ASSIGN- ORS TOv THE METALS EXTRAGTION CORPORATION LIMITED, 0F LONDON, ENGLAND.

EXTRACTION 0F METALS FROM THEIR GRES.

Specification of Letters Patent.

Application led .lune 25, 1910.

Patented Nov. es', 1911.

serial No. 568,904.

The accompanying drawing is a diagram T 0 all whom it may concern Be it known that we, WOLDEMAR HoMMnL, Ph. D., a citizen of the Swiss Confederation, and lluxnr THOMAS DUnxN'r, a subject of the King of England, both residing in London, England, have invented certain new and useful Inlprovements in the Extraction of Metals from Their Orcs, of which the following is a specification.

lhis invention relates to improvements in the extraction of metals from their ores, and has special reference to the extraction of zinc and copper from their ores, by means of sulfurous acid.

More particularly the invention refers to the extraction of such metals from sultid ores.

A method of treating ores according to this invention for extracting metals such as zinc or copper, consists -in subjecting a solu tion of the metal to the action of a hot gas to precipitate the metal or a compound thereof, thereafter bringing the cooled resultant gas into contact with a mixture of ore and water to effect a solution of the metal.

More particularly this invention consists in subjecting a mixture of the roasted ore and water to the action of sulfur-ous acid gas escaping from the ore roasting furnace and previously cooled, collecting the sultite solution of zinc or copper thus formed and submitting it to the action of hot gases from the roasting furnace, the furnace gases be- .ing thereby cooled and enriched by the addition of the sulfurous acid driven olf from the sullite solutions and zinc monosulfite 0r metallic copper heilig precipitated.

This invention al. o has reference to apparatus for carrying out the above or other processes in which a cold gas is brought into contact witl'. a flowing mixture consisting of a mixture of ore and water, to elect a solution, after which the liquid solution is treated with hot gases to effect a precipitation. The apparatus comprises a roasting furnace, a precipitating tower communicating therewith in which the sulfite solution is subjected to the action of the escaping hot gases from the roasting furnace and the extraction tower communicating with the lprecipitating tower wherein the cooled gases are caused to act upon a mixture of ore and water passing through the extraction tower.

in elevation and partly in section showing one form of apparatus suitable for carrying this invention into effect.

A is a feed hopper for ore and water.

B is a solution tower of any well known form suitable for bringing solids, liquids and gases into intimate contact.

C is a conduit for introducing sulfurous acid gas at the bottom of the tower B.

D is a roasting furnace of any form cus tomarily used for roasting sulfid orcs so as to yield sulfurous acid gas.

E is a precipitating tower of any well known kind in which a hot gas is Vbrought into contact with a liquid so as to transfer heat from the gas to the liquid.

F is a conduit to lead hot furnace gases (containing SO2) from the furnace to the bottom of the towel' E.

H is a decanting apparatus connected to the bottom of the solution tower B and arranged to receive the discharge from the tower B and to separate the liquid portion from the solid portion.

J is a conduit through which the li uid from the decanting. vessel H is conducte to the precipitating tower E.

K is a centrifugal liquid from the decantlng vessel H through the conduit J to the tower E. The liquld is caused to trickle over baies which may take the form of openta'nks G disposed within the towerE, by which the liquid may be exposed to the action of the-gas in the tower E.

This invention will now be described in its application to the extraction of zinc from complex sulid ores reference being madeto the accompanying drawing.

The roasted ore is mixed with water and is introduced through the feed hopper A to a'solution tower B where it is brought into contact with a gas containing sulfur-ous acid produced as hereinafter described. The sulfurous acid gas and the water react with the roasted ore so as to dissolve the zinc therefrom in the form of zinc hisulfite solution. The contents of the solution tower B are discharged into a decanting device H in which the insoluble residue settles out of the solution of zinc bisulite. 'I hissolution of zinc bisulte is drawn ott' from the dccanting vessel [l by means of a centrifugal pump Iii and is passed through the conduit pump to convey the J into Q-the" precipitating tower From the conduitd the solution runs on to the baies G `and `trickles down through the tower ,E through which the hot gases delivered from the roasting furnace D through the conduit l? vare passing in an upward direction. The Contact of the zinc bisulfite solution withr the hoty Gases from the fur! nace has two results. The Iliquid added cold removes the 'heat from the gases and it passes out of the tower E' through the conduit C in a cooled state.4 It is essential for the solution of zinc in the formvof bisulite, that the sulfurous acid as employed 'Should be cooled, and the method above described affords the required supply of cooled gas.

The other important operation which takes 'placein the tower E is that the furnace ases, being very hot, have. the effect of reakin'g up the solution of zinc bisulite and of expelling sulfurous acid gas therefrom. By this means the zinc bisulite is converted into zinc monosulfite which latter may be .easily precipitated7 collected and roasted in a calcining furnace to produce zinc oxid.l It will be seen that the hot furnace' gases are not only cooledL but ,the sulfurous acid gas escaping from .the bisulite solution'lenriches the furnace gases which are then passedin their cooled and enriched state-.to the extracting tower B for the treatnient of fresh quantities of roasted ore-and water. i

This process posseses many commercial advantages among w ich the following vare the niost prominent It is always necessary to cool the gases before they can,be used 'for extraction, and the heat which is usually wasted is 'now used to convert the zinc bisulfite into monosulite. l The furnace gases are at once enriched in sulfurous acid and the extraction is thereby enormously facilitated; also it is made possible to use gases poorer in sulfurous acid and to treat ores f'whchY originally did not contain sullicient sulfur.-

in the above described process reference has been made all through to the treatment It is within this invention to treat copperores such Vas malachite ore (carbonate of copper) or a copper slag; such materials not containing sulfur would go after crushing direct to the towers and the sulfur or sulter ore to give the ynecessary sulfurous acid gases from the roasting furnace could be obtained from any other source such as roasting ores which do not requirev to go through this particular extraction process after roasting.

' Although one particular method of carrying out this invention has been described modifications may be made provided that the spirit of the invention is notv departed from.

What we claim as our invention and desire to secure by Letters Patentis The herein described cyclic process for the extraction of zinc from its suliid ores in which the only reagents employedv are .Water and thosesupplied by the ore itself which consists in `roasting the ore/,to drive off gases containing sulfurous acid cooling said gases and bringing them in contact with a mixture of the roasted ore and water to effect the solution of the zinc as sulfite and thereafter submitting said sulte solus tion to the action of the hot gases from the ore roasting furnace whereby insoluble zinc monosultite is precipitated, the said hot gases being enriched in sulfurous acid and cooled ready for theV further treatment of the mixture of roasted ore and water.

In testimony whereof we have signed our names to this specification in the presence vof.

two subscribing witnesses.

WOLDEMAR HOMMEL. HENRY THOMAS DURANT.v

' Witnesses:-

vPliner Hnwrrr,

H. D. JAMESON. 

